CN109589131B

CN109589131B - Ultrasonic method and ultrasonic system for automatically setting Doppler imaging mode parameters in real time

Info

Publication number: CN109589131B
Application number: CN201811167164.8A
Authority: CN
Inventors: 马西莫·法拉吉
Original assignee: Esaote SpA
Current assignee: Esaote SpA
Priority date: 2017-10-03
Filing date: 2018-10-08
Publication date: 2022-02-22
Anticipated expiration: 2038-10-08
Also published as: CN109589131A; US20190099161A1; EP3467540A1; US11160536B2

Abstract

In order to speed up (fast) the examination time in an ultrasound system in a vascular examination procedure, it is necessary: automatically positioning the color doppler ROI and/or sampling gate in an optimal manner; selecting an optimal color Doppler/Beam-line steering angle; and setting a doppler correction angle. The algorithm is able to process the doppler signals in real time to identify the doppler regions where the most significant blood flow is present, and then analyze the "shape" of the color doppler regions that identify the location and direction of the "main" blood flow. The vascular examination procedure may be easier and faster.

Description

Ultrasonic method and ultrasonic system for automatically setting Doppler imaging mode parameters in real time

Technical Field

The invention relates to an ultrasonic method and an ultrasonic system for automatically setting parameters of a color Doppler imaging mode in real time.

Background

The ultrasound imaging system may alternatively or in combination operate in multiple imaging modes that provide different views, and thus different features of the imaged object. Among the different modes, the most common are:

a B-mode for imaging of tissue,

doppler mode for flow analysis and imaging.

Typical Doppler modes include Power Doppler (Power Doppler) mode for tissue motion and blood Flow imaging, Color Flow Doppler (Color Flow Doppler) mode for qualitative blood Flow imaging, and Spectral Doppler (Spectral Doppler) mode for blood Flow quantification.

The doppler image data may relate to single-dimensional images, two-dimensional images (2D) and three-dimensional images (3D). Also, the methods and systems described herein may be used to acquire single-dimensional, two-dimensional, and three-dimensional images.

During a vascular examination by an ultrasound imaging system, a color flow doppler imaging mode is often used to examine the anatomy of the blood vessel and provide a diagnosis as to the presence of vascular disease.

The vessel examination procedure comprises performing operations for locating a Color Doppler roi (Color Doppler roi) and/or a Doppler sampling Gate (Doppler Sample Gate) in an optimal manner and/or selecting an optimal Color Doppler-beam line Steering angle (Color Doppler-beam Steering angle) and/or setting a Doppler Correction angle (Doppler Correction angle). Performing these operations manually is time consuming and increases inspection time and cost. Currently, different techniques can be used to perform the above operations in real time and automatically.

The prior art includes different methods for automatically setting the optimal positioning of the color doppler ROI and/or the doppler sampling gate and/or the optimal color doppler-beam line steering angle and/or doppler correction angle, but these known methods cannot operate in a fully automatic manner and in real time, in particular when following changes in the scanned object (e.g. moving the probe).

US2014/0221838 describes an ultrasound system that uses vessel segmentation and blood flow image analysis to automate color box placement, doppler sample volume placement, angle correction, and beam steering angle.

US6,322,509 describes a method for automatically adjusting the position and size settings of a doppler sampling gate based on blood vessel image data. The vessel segment is searched using an object search technique of geometric and morphological information in a binarized vessel image obtained only from B-mode or color blood flow image data. The morphologically best or closest vessel segment within the target search region in the two-dimensional image is found. The sampling gate is placed at or near the center of the target vessel segment and the size of the sampling gate is adjusted relative to the vessel size. The best available steering angle that minimizes the doppler angle is selected.

In US8,047,991, direction and/or orientation is automatically identified in an ultrasound image by using a region contraction procedure or by using a location associated with blood flow or tissue structures.

In US5,690,116, a histogram based approach is disclosed. According to this document, the angle enclosed by the direction of the ultrasound echo beam and the vessel axis (defined as the doppler angle) is automatically measured in an echographic image based on the initial point Pi in the previously specified vessel. The first isotropic ray tracing from the initial point Pi is used to generate a histogram of the gray levels of the ray points. An algorithm is then applied to the histogram to classify the gray levels of the selected points. A second ray tracing is performed which is limited to the vessel wall and provides information for determining the slope of the regression line and the calculation of the doppler angle.

There is a need for a method and system for automatically setting parameters of a color doppler imaging mode in real time, in particular automatically positioning a color doppler ROI and/or a sampling gate in an optimal manner and/or automatically selecting an optimal color doppler or beam line steering angle and/or automatically setting a doppler correction angle, not only in response to user actions but also in adaptation to changes in the scanned object (e.g. moving the probe), which provides faster and easier vessel examination procedures.

Disclosure of Invention

It is an object of the invention to provide a method for automatically measuring the doppler angle of a blood vessel in an echographic image starting from a specified point.

Another object is to provide an accurate and fast method for automatically measuring the doppler angle.

Another object is to provide an ultrasound system configured to perform the above-mentioned measuring method.

According to a first aspect, a method for automatically setting parameters of a color doppler imaging mode in real time comprises the steps of:

-transmitting an ultrasound beam in the object and receiving a reflected beam from the object;

-extracting a color doppler signal from the reflected beam;

-processing the color doppler signals to identify a region where the color doppler signals indicate the presence of blood flow, and processing the color doppler signals associated with the region to automatically determine one or more of the following parameter settings:

optimally locating the color doppler ROI and/or doppler sample gate, determining and applying the optimal color doppler beam steering angle, setting the doppler correction angle,

-processing the color doppler signal comprises:

analyzing the shape of the identified color doppler region by processing the corresponding color doppler signal to determine:

a) the location of the blood flow with the most significant intensity;

b) the direction of blood flow at the location determined in a);

determining the optimal position of the color Doppler ROI and/or the Doppler sampling gate according to the position of the blood flow, and positioning the color Doppler ROI and/or the Doppler sampling gate at the position;

the steering angle and/or doppler correction angle of the transmit beam is determined from the direction of blood flow.

According to one embodiment, the operation of analyzing the shape of the identified color doppler region is based on morphological features of blood flow determined from the color doppler flow signals.

In another embodiment, analyzing the shape of the identified color doppler region includes creating a virtual doppler image of blood flow from the color flow signals.

According to one embodiment, determining the location of the blood flow having the most significant intensity comprises:

-optionally sampling and/or filtering the virtual doppler image;

-calculating the maximum value of a pixel or voxel of the virtual doppler image and selecting the position of this pixel or voxel as the position of the blood flow.

In combination with one or more of the above embodiments, in a further refinement determining the direction of blood flow comprises:

-applying four directional filters to the virtual doppler image at the location of the pixel having the maximum value, the directional filters being respectively oriented along one of four directions, each direction being rotated by 45 ° with respect to the adjacent direction;

-combining the outputs of the four directional filters to obtain a vector;

-determining the direction of the blood flow from the direction of the vector.

According to embodiments herein, determining the direction of blood flow comprises:

-applying four directional filters to the virtual image at the location of the pixel having the maximum value, the directional filters being oriented along the following directions, respectively: according to the symbols 0 ° -180 °, 45 ° -215 °, 90 ° -270 ° and 135 ° -315 °, the direction being oriented by a direction defined by an axis passing through the direction of an goniometer centred on the central position of the flow, the goniometer being aligned with the axis of a cartesian system defining two dimensions of an image having axes 0 ° -180 ° and 90 ° -270 °;

-combining the outputs of the four directional filters forming a vector with orthogonal components x and y having the following values: x ═ the output of the filter with direction 0 ° -180 ° - (the output of the filter with direction 90 ° -270 °), and Y ═ the output of the filter with direction 45 ° -215 ° - (the output of the filter with direction 135 ° -315 °;

-determining the phase of the vector and calculating the angle of the blood flow direction from the phase.

According to one embodiment, the virtual doppler image from which the direction is calculated is sub-sampled, in particular by a factor of 2.

According to another variant embodiment, the virtual doppler image is filtered by a smoothing filter.

According to one embodiment, the function used to determine the direction of blood flow is:

according to a further refinement, the normalized modulus Q of the vector can be calculated and used as a quality factor or quality factor for the direction estimation.

Embodiments provide a function for calculating the normalized modulus Q of a vector as:

wherein:

f0 is the output of the filter with a direction of 0-180;

f45 is the output of the filter with a direction of 45-215;

f90 is the output of the filter with a direction of 90-270;

f135 is the output of the filter with a direction of 135-315.

According to one embodiment, the method provides the following additional steps:

-defining a threshold value for the value of the normalized modulus of the vector determined according to one or more of the embodiments described above;

-calculating the normalized modulus Q;

-comparing the calculated value of the normalized modulus with a threshold value;

-setting an optimal color doppler beam axis steering angle and doppler correction angle based on the blood flow direction calculated from the phase of the same vector that calculated the normalized modulus if the calculated value of the normalized modulus is above a threshold.

According to another aspect, there is provided an ultrasound imaging system comprising:

-an ultrasound probe comprising an array of transducers, the probe emitting ultrasound beams in a target region where blood flow is present and receiving echo signals reflected by the target region;

-a beamformer which controls the direction in which the probe emits ultrasound beams;

-a doppler processor for generating a doppler signal from the echo signal;

-an image processor producing a doppler image of blood flow in the target region;

-a color doppler ROI and/or doppler sample gate positioning processor for automatically positioning the ROI and/or sample gate in an optimal position relative to the imaged blood flow;

-a steering angle and/or doppler correction angle processor for automatically determining an optimal steering angle and setting a corresponding optimal correction angle for the ultrasound beam propagation direction;

-a color doppler ROI and/or doppler sample gate positioning processor and a steering angle and/or doppler correction angle processor are configured to process the color doppler flow signals, determine data related to morphological features of the blood flow, and calculate from the morphological feature data the optimal position of the color doppler ROI and/or doppler sample gate and the steering angle and/or doppler correction angle.

According to one embodiment, the positioning processor is arranged in combination with a color doppler image processing unit, which generates an image from the color doppler signals and is configured to determine the maximum pixel value and the location of the corresponding pixel, the color doppler image processing unit comprising a ROI and/or sampling gate management unit, which automatically positions or centers the ROI and/or sampling gate at the location of the pixel having the maximum value.

According to another embodiment the steering angle and/or doppler correction angle processor is arranged in combination with the color doppler image processing unit to generate images from color doppler signals, and the steering angle and/or doppler correction angle processor comprises a filter unit provided with four directional filters, each directional filter being oriented in one of four directions, respectively, each direction being rotated by 45 ° with respect to the adjacent direction.

The outputs of the four directional filters are connected to a steering angle and/or doppler correction angle processor configured to calculate the blood flow direction and a quality factor of the calculated direction.

According to one embodiment, the positioning processor comprises a sampling unit for subsampling the color doppler image and optionally a smoothing filter of the subsampled image.

According to one embodiment, the steering angle and/or doppler correction angle processor comprises a sampling unit for subsampling the color doppler image.

In another embodiment, the steering angle and/or doppler correction angle processor includes a memory for storing a threshold value of the quality factor and a comparator for comparing the calculated quality factor to the threshold value, the output of the comparator being read by the steering angle and/or doppler correction angle processor for determining whether the calculated flow direction can be used to determine the steering angle and/or doppler correction angle of the transmit beam.

According to one embodiment, a program is loaded and executed by the steering angle and/or doppler correction angle processor that configures the processor to calculate a function of blood flow direction and quality factor from the outputs of the four directional filters as follows:

where X and Y are the components of a vector determined by combining the outputs of the four directional filters, the function is as follows:

X-F0-F90, and Y-F45-F135

Wherein:

f0 is the output of the filter with a direction of 0-180;

f45 is the output of the filter with a direction of 45-215;

f90 is the output of the filter with a direction of 90-270;

f135 is the output of the filter with a direction of 135-315.

And the quality factor corresponds to a normalized modulus of a vector having the above defined components X and Y, wherein:

and wherein F0, F45, F90, F135 are according to the above definition.

As can be seen from the above embodiments, determining the optimal position of the color doppler flow and/or the sampling gate, as well as the optimal steering angle of the transmit beam and the corresponding doppler correction angle, is a very simple operation that can be performed quickly. Thus, when using the method and system according to the above embodiments, the optimal ROI position and/or the optimal sampling gate position and the optimal steering angle and doppler correction angle can be determined very fast and in real time, without introducing any delay slowing down the speed of the vessel examination procedure, making the procedure easier and faster.

Furthermore, the simplicity of the calculations to be performed and the generality of the entire automated process allow any changes related to the scanned object (e.g. while moving the probe) to be followed automatically.

In implementing the method in an ultrasound system, since the procedure basically comprises a specific processing of the signals received and generated in any case by the existing and conventional units of the ultrasound scanner, the steering angle and/or doppler correction angle processor and the positioning processor may be general-purpose processors which are already provided in the ultrasound system and in which a program is loaded and executed, in which program the steps of the method according to one or more of the above-described embodiments are encoded in the form of instructions which configure the general-purpose processor and the peripherals connected thereto to carry out the functions of the operating units required for carrying out the steps of the method.

According to another aspect, a readable medium is provided in which instructions are encoded to configure a general-purpose processor and optionally peripherals connected thereto, such that the processor and one or more of the peripherals perform the functions of the operating unit required for performing the method, the medium being readable by a reader unit or stably installed as a peripheral to the processor. Non-exhaustive examples of such media are CD ROM, CD-RAM, DVD-ROM, DVD-RAM, memory cards, USB memory sticks, portable hard disks, internal hard disks and other similar devices.

Drawings

FIG. 1 shows a block diagram of an ultrasound system according to one embodiment.

FIG. 2 shows a block diagram of an embodiment of a positioning processor and a steering angle and correction angle processor.

Figure 3 schematically shows a blood vessel, a beam direction, a blood flow direction and a sampling gate.

Fig. 4 shows a coordinate system in which the components of the output data of the directional filter combined with the vector are graphically depicted.

Fig. 5 shows an output image of the effect of each directional filter on the blood flow image.

FIG. 6 is a flow chart showing the steps of a method for automatically locating a color Doppler ROI and/or sampling gate and for automatically determining steering and correction angles.

FIG. 7 illustrates a block diagram of an ultrasound system formed in accordance with an alternative embodiment.

Fig. 8 shows a block diagram of a portion of a digital front end panel.

Fig. 9 shows a block diagram of a digital processing board.

Detailed Description

While multiple embodiments are described, other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings, which show and describe illustrative embodiments of the disclosed subject matter. It will be understood that the inventive subject matter is capable of modification in various respects, all without departing from the spirit and scope of the described subject matter. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

FIG. 1 illustrates a high-level block diagram of an ultrasound system implemented according to embodiments herein. Portions of the system, defined by various functional blocks, may be implemented by dedicated hardware, analog and/or digital circuitry, and/or one or more processors operating on program instructions stored in a memory. Additionally or alternatively, all or part of the system may be implemented using digital components, Digital Signal Processors (DSPs) and/or Field Programmable Gate Arrays (FPGAs), and the like. The blocks/modules shown in fig. 1 may be implemented in dedicated hardware (DPS, FPGA, memory) and/or in software using one or more processors.

The ultrasound system of figure 1 includes one or more ultrasound probes 101. The probe 101 may include various transducer array configurations, such as a one-dimensional array, a two-dimensional array, a linear array, a convex array, and so forth. The transducers of the array may be managed to operate a 1D array, a 1.25D array, a 1.5D array, a 1.75D array, a 2D array, a 3D array, a 4D array, and so forth.

The ultrasound probe 101 is connected to a beamformer 103 by a wired or wireless link. The beamformer 103 includes a Transmit (TX) beamformer and a Receive (RX) beamformer, which are collectively represented by the TX/RX beamformer 103. The RX portions of the beamformer and RX portions may be implemented together or separately. The beamformer 103 provides transmit signals to the probe 101 and performs beamforming of "echo" receive signals received by the probe 101.

The TX waveform generator 102 is connected to the beamformer 103 and generates transmit signals that are provided from the beamformer 103 to the probe 101. The transmit signals may represent various types of ultrasound TX signals, such as signals used in connection with B-mode imaging, doppler imaging, color doppler imaging, pulse inversion transmit techniques, contrast-based imaging, M-mode imaging, and so forth. Additionally or alternatively, the transmission signal may comprise a single or multiple line transmission, a shear wave transmission signal, or the like.

The beamformer 103 performs beamforming of the transmit beams to gradually focus the transmit beams along different adjacent lines of sight covering the entire ROI. The beamformer also performs beamforming on the received echo signals to form beamformed echo signals that are associated with pixel locations distributed over the region of interest. For example, according to some embodiments, the transducer elements produce raw analog receive signals that are provided to a beamformer. The beamformer adjusts the delays to focus the receive signals along one or more selected receive beams and at one or more selected depths within a region of interest (ROI). The beamformer adjusts the weights of the received signals to obtain the desired aperture barriers and contours. The beamformer applies weights and delays to the received signals from each respective transducer of the probe. The delayed weighted received signals are then summed to form a coherent received signal.

The beamformer 103 includes (or is coupled to) an a/D converter 124, the a/D converter 124 digitizing the received signal at a selected sampling rate. The digitization process may be performed before or after the summation operation that produces a coherent received signal.

Alternatively, the dedicated sequencer/timing controller 110 may be programmed to manage the acquisition timing, which may be summarized as a sequence of transmissions for selected reflection points/targets in the ROI. The sequence controller 110 manages the operation of the TX/RX beamformer 103 in relation to transmitting ultrasound beams and measuring image pixels at various LOS locations along the line of sight. Sequence controller 110 also manages the collection of received signals.

The one or more processors 106 perform various processing operations as described herein.

According to embodiments herein, the beamformer 103 includes an output configured to connect to the ultrasound probe 101 and transmit signals to the transducer elements of the probe 101.

According to one embodiment herein, the sequencer 110 controls the beamformer to generate and transmit a plurality of transmit beams that are focused to display an aperture or transmit beamwidth that contains a number of aim or receive lines. The plurality of transmit beams are progressively moved laterally along the array of transducer elements of the probe, and thus laterally along the ROI, to scan the entire ROI. As long as the line of sight or receiving line position falls within the aperture of the emitted beam or within the width of the emitted beam, a certain number of different multiple emitted beams will encompass a certain line of sight or a certain receiving line. Thus, for a reflection point on a certain receive line or line of sight within the ROI and having a particular line position relative to the transducer array of the probe, a certain number of receive signals from different transmit beams are received, the central transmit line of the transmit beam having a different lateral offset relative to the reflection point and the corresponding receive line.

The received data relative to the echoes from the reflection points is a combination of the received signals from the reflection points of a number of transmitted beams.

According to embodiments herein, the beamformer 103 comprises an input configured to connect to the ultrasound probe 101 and to receive signals from the transducers of the ultrasound probe 101. The memory 105 stores time delays to align the reflected signals received by the transducer array of the probe 101 from the reflectors in the ROI. The memory 105 also stores phase corrections to correct for phase differences contributed by the receive signals of each transducer element derived from each of a number of different laterally offset transmit beams relative to a receive line or line of sight in which the reflection point lies.

A delay/phase correction (DPC) module 104 is connected to the memory 105 and provides various delays and corrections to the beamformer 103. For example, DPC module 104 instructs beamformer 103 to apply time delays and phase corrections to the received signals to form delayed received signals. The beamformer 103 then coherently sums the delayed receive signals to obtain coherent receive signals related to the reflection point or reflection target.

Alternatively, memory 105 may store common phase shift corrections associated with multiple channels. Where multiple receive signals are received along a common receive line location, different phase shift corrections may be stored with the various respective channels, but due to the number of different transmit beams, each transmit beam has a laterally offset transmit centerline and an aperture or width surrounding the receive line location. Memory 105 may also store weights (e.g., barrier weights and/or RTB weights).

As explained herein, the beamformer 103 (circuitry) is configured to simultaneously apply beamforming focusing delays and phase shift equalization delays (so-called RTB delays) to each received signal from each transducer element of a reflection point. The beamforming focusing delay is calculated from the arrival time of the signal at the transducer element as it travels from the reflection point to the transducer element, and the varying phase shift equalizing delay is determined from the phase difference of the wavefront phase of the arriving reflection point relative to the wavefront phase of the further transmitted beams arriving at the same reflection point and laterally offset from each other.

Alternatively, the memory 105 may store a pre-calculated table, wherein the pre-calculated table comprises the actual arrival times of the received signals relative to the predetermined reflection points. Alternatively, the processor 106 may be configured to calculate the actual arrival time of the received signal relative to the predetermined reflection point. Alternatively, the memory 105 may store a pre-calculated table, wherein the pre-calculated table includes pre-calculated phase shift equalization delays that are applied simultaneously with beamforming focusing delays to receive signals of receive lines along a particular line of sight or to a certain receive line position derived from a number of transmit beams that are differently laterally offset relative to the receive line position, the number of transmit beams being set by setting a particular aperture or lateral width of the transmit beams. Optionally, the memory 105 may store a pre-computed table of pre-computed phase shift equalization delays for one or more of the different transmit beam apertures or widths.

Optionally, the processor 106 may be configured to calculate the phase shift equalization delay for one or more of the different transmit beam apertures or widths.

Optionally, the beamformer 103 circuitry may further comprise a summing unit to add beamforming delays and phase shift equalization delays (RTB delays) to the received signals derived from each reflection point.

According to some embodiments, at least a portion of the beamforming process may be implemented by the processor 106 (e.g., in conjunction with software RTB beamforming). For example, the memory 105 may store beamforming related program instructions that are implemented by the processor 106 to apply beamforming delays and phase shift equalization delays to received signals simultaneously.

The processor 106 and/or the CPU112 also perform conventional ultrasound operations. For example, the processor 106 executes a B/W module to generate a B mode image. The processor 106 and/or the CPU112 execute a doppler module to generate a doppler image. A processor executes a Color Flow Module (CFM) to generate a color flow image. The processor 106 and/or the CPU112 may implement additional ultrasound imaging and measurement operations. Optionally, the processor 106 and/or the CPU112 may filter the first and second displacements to eliminate motion-related artifacts.

The image scan converter 107 performs scan conversion on the image pixels to convert the format of the image pixels from the coordinate system of the ultrasound acquisition signal path (e.g., beamformer, etc.) and the coordinate system of the display. For example, the scan converter 107 may convert image pixels from polar coordinates to Cartesian coordinates of the image frame.

The image memory 108 stores a set of image frames over time. The image frames may be stored in polar, cartesian or another coordinate system format.

The image display 109 displays various ultrasonic information, such as image frames and information measured according to embodiments herein. The display 109 displays an ultrasound image with the region of interest shown.

The control CPU module 112 is configured to perform various tasks such as implementing user/interface and overall system configuration/control. In the case of a software-fully implemented ultrasonic signal path, the processing node typically also carries the functions of a control CPU.

The power supply circuit 111 is provided to supply power to various circuits, modules, processors, memory components, and the like. The power source 111 may be an ac power source and/or a battery power source (e.g., associated with portable operation).

According to one embodiment, the ultrasound system of FIG. 1 is provided with a localization, steering angle and correction angle processor, indicated at 161. The processor is configured to determine in an automated manner an optimal position of a flow or an optimal position of a doppler sampling gate in a target region of a region of interest (ROI) relative to a blood vessel or color doppler blood flow. Further, the processor 161 calculates an optimal steering angle of the transmit beam for acquiring the doppler signals and data and an optimal doppler correction angle.

Fig. 3 shows a schematic view of a target area, wherein a blood vessel 300 accommodates blood flow. At 310, a beam direction is indicated that is at an angle to the non-beam propagation direction of the emitted beam produced by the probe and, in the case of a planar array, is generally substantially perpendicular to the surface of the transducer array or perpendicular to a slice of the curved surface of the curved array. In fig. 3, a steering angle β and a correction angle α are shown, the correction angle α being the angle between the direction of blood flow, indicated by 320, and the steering transmit beam direction or propagation axis 310.

Since the doppler data is based on a phase shift between the transmitted beam and the reflected beam due to motion, the motion must have at least a component parallel to the transmitted beam, otherwise there will be no doppler contribution in the reflected beam. Since it is clear that a correct positioning of the ROI or sampling gate G and a determination of the optimal steering angle and correction angle are essential for the quality of the doppler data, the best possible color doppler information of the blood flow is obtained.

In the embodiment of fig. 1, the processor 161 receives color doppler signals from the color doppler processor CFM and determines the morphological characteristics of the blood flow and the corresponding blood vessels in the target region. Based on this feature, the processor automatically calculates the optimal positioning of the ROI and/or sample gate and the optimal steering and correction angles of the ultrasound beam. The optimal positioning of the ROI is determined by finding that the pixel in the image corresponding to the color doppler signal is the maximum of the image pixel. The pixel or the position of these pixels is set as the position of the ROI or the sampling gate. This information is transmitted to the CFM processor or CPU112 for operating ROI positioning in the display image according to the system architecture as described above.

In order to determine the optimal steering angle of the ultrasound beam and/or the optimal correction angle applied by the processor, four directional filters are set according to four different directions, at the position of the pixel having the maximum value determined in the previous step and in the image reproducing the color doppler signal or data. The outputs of the filters are then combined to generate a component of a vector whose direction is the direction of blood flow. The processor 161 also determines a quality factor from the output signals of the four directional filters, which quality factor corresponds to the normalized modulus of the vector and is a measure for evaluating the quality of the blood flow direction determined by the vector.

This is shown in fig. 4 and will be described in more detail later.

The processor determines the steering angle and the correction angle from the determined blood flow direction if the quality factor is above a certain threshold, which may be set by the user and/or by the manufacturer and installer of the system and which may be based on empirical data obtained during the setup and adjustment.

FIG. 2 shows a block diagram of an embodiment of a positioning, steering angle and correction angle processor. According to the principles of this embodiment, the calculation of the optimal position of the color doppler ROI and/or the sampling gate G is performed on the image data. The image data may comprise a virtual doppler image composed by a dedicated processor or may be obtained from the power output of a CFM processor (e.g., in accordance with the system architecture of fig. 1). The virtual image generator 200 of fig. 2 will be understood to encompass two variations. The positioning processor comprises a sampling unit configured to sub-sample the virtual image (e.g. by a factor of 2). The subsampled image is further processed by a smoothing filter 202 and the filtered image is processed by a maximum identifier 203 and a pixel position detector recording the pixel position of the maximum. This position data is saved and used by the ROI and sample gate positioner 205, which generates data of the ROI and sample gate positions, to provide to an image generation chain, such as to a CFM processor interface 206 (e.g., the CFM processor shown in fig. 1) in communication with the CFM processor. The position information in the virtual image with the pixel maximum is provided to the steering angle and correction angle processor. The processor also operates on the virtual image provided by the virtual image generator 200 and applies the subsampled image data to four different directional filters, each set in a different direction, after submitting the image through the subsampling unit 211 to subsampling by a factor of 2 or higher or a factor different from 2. The direction is set according to a series of different directions each of which changes by an angular displacement of 45 deg. with respect to the previous direction. The directional filter 212 is centered at a location in the image that corresponds to the location determined by the location processor that has the pixel maximum. The output of the directional filters collectively indicated by 212 is processed by a processing unit 213, the processing unit 213 being configured to execute an algorithm for determining directional data of the blood flow and a quality factor of the directional data based on which the steering angle and the correction angle are set.

The steering angle calculator 214 calculates an optimal steering angle and an optimal correction angle out of the blood flow direction and is controlled by the output of the quality factor comparator 215, which quality factor comparator 215 compares the quality factor with a threshold value and triggers the calculation of the steering angle and the correction angle according to the blood flow direction only when the quality factor is higher than the threshold value. If this is not the case, the process is repeated. This new cycle can start from the very beginning, i.e. by calculating again the position of the maximum pixel value in the image, or by restarting the process of sub-sampling, directional filtering and calculating the steering angle and correcting the direction of blood flow within the angle processor.

When repeating the loop by starting from either of the two starting steps described above, a new loop may be performed by changing at least one parameter of the process, for example by changing the subsampling factor or the setting of the smoothing filter.

According to a variant embodiment, if the quality factor is still below the defined threshold after a certain preset number of repetitions of the cycle, the process is stopped and the blood flow direction associated with one of the calculated quality factors is used as the blood flow direction on the basis of which the steering angle and the correction angle are determined.

Different variations of selecting the direction of blood flow are possible under the above conditions. According to a first variant, a blood flow direction is selected which corresponds to a quality factor close to the threshold value. In another variation, the blood flow direction is calculated as an average of the different blood flow directions generated for each repeating cycle. In this case, the quality factor for each flow direction may be used to calculate a weighted average to determine the corresponding weight. In one embodiment, the weight associated with each blood flow direction is calculated from the difference between the quality factor corresponding to the blood flow direction and a threshold. The function may be linear or non-linear such that a blood flow direction with a higher difference between a corresponding quality factor and a threshold is further penalized (penalized) with respect to a blood flow direction with a lower difference between a corresponding quality factor and a threshold.

The steering angle and correction angle data is provided to the beamformer 103 for application to the transmit beams.

As already noted above with respect to the embodiment of fig. 1, the positioning processor and the steering angle and correction angle processor may be implemented at least in part with dedicated hardware (defined by various functional blocks), analog and/or digital circuitry, and/or one or more processors operating program instructions stored in memory. Additionally or alternatively, all or part of the processor may be implemented using digital components, Digital Signal Processors (DSPs) and/or Field Programmable Gate Arrays (FPGAs), etc. The blocks/modules shown in fig. 2 may be implemented in dedicated hardware (DPS, FPGA, memory) and/or software with one or more processors.

The directional filter may be designed for any direction within a given space. For images, x-and y-directional filters are typically used to calculate the derivatives in the respective directions. The following array is an example of a 3 by 3 kernel for an x-direction filter (the y-direction kernel is the transpose of this kernel):

the above array is an example of one possible kernel of an x-direction filter. Other filters may include more weights in the center of the non-zero columns. The directional filter and example code are described in http:// normal-www.dartmouth.edu/doc/idl/html _6.2/Filtering _ an _ imagehvr. ht ml.

Fig. 5 shows an example of placing a directional filter at the position of the maximum on the subsampled color doppler image 500 and setting four filter directions. The goniometer 505 shows the direction defining symbol used in the specification and claims. The direction indicated briefly by 0 °, 45 °, 90 °, 135 ° in the image denoted 500 is defined by a goniometer connecting the axes of the two angular positions, so that the symbol 0 ° corresponds to the direction of the axes 0 ° -180 °, 45 ° corresponds to the direction of the axes 45 ° -225 °, 90 ° corresponds to the direction of the axes 90 ° -270 ° and 135 ° corresponds to the direction of the axes 135 ° -315 °. The goniometer is aligned with the direction of a reference coordinate system having orthogonal axes.

Graphical representations of the effect of each of the four directional filters are shown at 501 to 504 in figure 5.

Fig. 6 shows a flow chart of a method for automatically determining the optimal positioning of the color doppler ROI and/or the sampling gate G and for selecting the optimal color doppler beam direction steering angle and setting the doppler correction angle.

At step 600, a color doppler flow image is generated from the color doppler flow signals. These image data are sub-sampled at step 610.

According to a preferred embodiment, the subsampling is performed by a factor of 2. At step 630, the subsampled image 620 is filtered by a smoothing filter. The filtered image 640 is then submitted to a search algorithm in step 650 to find the largest pixel or pixel value and identify the location indicated by the image 660 by an arrow.

This position is the position used to locate the ROI and/or sample gate. Further, this position is a position where the directional filter has to be located.

Starting with the sampled image 620, at step 670, four directional filters are applied to the image at the pixel location corresponding to the maximum value. In step 680, the outputs of the directional filters are combined to calculate a quality factor of the direction and the calculated direction in order to determine whether the calculated direction is reliable and can be used as a reference direction for setting the steering angle and the doppler correction angle of the beam direction. At step 690, the direction of blood flow resulting from the combination of the filter outputs at step 680 is shown and indicated by an arrow.

The outputs of the four directional filters are defined by the directions of 0-180 of F0, 45-225 of F45, 90-270 of F90, and 135-315 of F135, the flow direction being calculated from the phase of a vector having components x and y as shown in FIG. 4, where component x is calculated as the difference in the filter outputs aligned in the directions of 0-180 and 90-270:

X＝F0-F90；

similarly, the component y is calculated as the difference of the filter outputs aligned in the 45 ° -215 ° and 135 ° -315 ° directions:

Y＝F45-F135。

the phase is calculated according to the following function:

the quality factor is calculated according to the following function, which corresponds to the definition of the normalized modulus of the vector with component X, Y:

this value is used in conjunction with a threshold for determining the reliability of the estimate. If the comparably calculated quality factor Q value is above a threshold value, the estimated blood flow direction is considered reliable and used for determining the steering angle and the correction angle. If the quality factor is below the threshold, the direction estimate is not reliable and the process is repeated to calculate a new blood flow direction.

Repetition may be performed in accordance with one or more of the different variations and implementations described above with respect to fig. 2.

FIG. 7 illustrates a block diagram of an ultrasound system formed in accordance with an alternative embodiment. The system of fig. 7 implements the operations described in the various embodiments. As an example, one or more circuits/processors within the system implement the operations of the figures and/or any of the processes described herein. The system includes a probe interconnect board 702, the probe interconnect board 702 including one or more probe connection ports 704. The connection port 704 may support various numbers of signal channels (e.g., 128, 192, 256, etc.). The connector port 704 may be configured for use with different types of probe arrays (e.g., phased arrays, linear arrays, curved arrays, 1D, 1.25D, 1.5D, 1.75D, 2D arrays, etc.). The probe may be configured for different types of applications, such as abdominal, cardiac, obstetrical, gynecological, urological and cerebrovascular examinations, breast examinations, etc.

One or more of the connection ports 704 may support the acquisition of 2D image data and/or one or more of the connection ports 704 may support 3D image data. By way of example only, 3D image data may be acquired by physical movement of the probe (e.g., mechanical scanning or physician movement) and/or by electrically or mechanically manipulating the probe of the transducer array.

A Probe Interconnect Board (PIB)702 includes switching circuitry 706 for selecting between connection ports 704. The conversion circuit 706 may be manually managed based on user input. For example, the user may designate the connection port 704 by selecting a button, switch, or other input on the system. Alternatively, the user may input a selection to select the connection port 704 through a user interface on the system.

Alternatively, the switching circuit 706 may automatically switch to one of the connection ports 704 in response to detecting the presence of a mating connection of the probe. For example, the translation circuit 706 may receive a "connect" signal indicating that a probe has been connected to a selected one of the connection ports 704. The probe head may generate a connection signal when power is initially supplied to a probe connected to the connection port 704. Additionally or alternatively, each connection port 704 may include a sensor 705 that detects when a mating connection on the cable of the probe has been interconnected with the corresponding connection port 704. Sensor 705 provides a signal to translation circuit 706, and in response to the signal, translation circuit 706 connects the corresponding connection port 704 to PIB output 708. Optionally, sensor 705 may be configured as a circuit that provides contacts at connection port 704. When no mating is connected to the corresponding connection port 704, the circuit remains open. When the mating connector of the probe is connected to the connection port 704, the circuit is closed.

Control lines 724 carry control signals between the probe interconnect board 702 and the digital processing board 724. A power line 736 provides power from the power supply 740 to the various components of the system, including but not limited to the Probe Interconnect Board (PIB)702, the digital front end board (DFB)710, the Digital Processing Board (DPB)726, the Main Processing Board (MPB) 744, and the User Interface Control Board (UICB) 746. A temporary control bus 738 interconnects and provides temporary control signals between the power supply 740 and the

boards

702, 710, 726, 744, and 746. The power supply 740 includes a cable connected to an external AC power source. Alternatively, the power supply 740 may include one or more power storage devices (e.g., batteries) that provide power when the AC power source is interrupted or disconnected. The power supply 740 includes a controller 742 that manages operation of the power supply 740, including operation of the storage device.

Additionally or alternatively, the power source 740 may include an alternative power source, such as a solar panel or the like. One or more fans 743 are connected to the power source 740 and managed by the controller 742 to turn on and off based on operating parameters (e.g., temperature) of various circuit boards and electronic components within the overall system (e.g., to prevent overheating of various electronic devices).

The digital front end plate 710 provides an analog interface to probes connected to the probe interconnect board 702. DFB710 also provides pulsing or control and drive signals, manages analog gain, includes analog-to-digital converters associated with each receive channel, provides transmit beamforming management and receive beamforming management and vector synthesis (associated with focusing during receive operations).

The digital front end board 710 includes transmit driver circuitry 712 that generates transmit signals that are communicated through respective channels to respective transducers associated with the ultrasonic transmit operation. The transmit driver circuit 712 provides pulses or controls for each drive signal and transmits beamforming management to direct transmit operations to a point of interest within the region of interest. As an example, a separate transmit driver circuit 712 may be provided in conjunction with each separate channel, or multiple channels may be driven with a common transmit driver circuit 712. The transmit driver circuitry 712 cooperates to focus the transmit beam to one or more selected points within the region of interest. The transmit driver circuitry 712 may implement single line transmission, encoding transmit sequences, multi-line transmitter operation, generating shear wave induced ultrasound beams, and other forms of ultrasound transmission techniques.

The digital front end board 710 includes a receive beamformer circuit 714 that receives echoes or receive signals and performs various analog and digital processing thereon, as well as phase shifting, time delay, and other operations related to beamforming. The beamformer circuit 714 may implement various types of beamforming such as single line acquisition, multiline acquisition, and other ultrasound beamforming techniques.

The digital front end plate 716 includes a continuous wave doppler processing circuit 716 configured to perform continuous wave doppler processing on the received echo signals. Optionally, the continuous wave doppler circuit 716 may also generate a continuous wave doppler transmit signal.

The digital front end board 710 is connected to a digital processing board 726 by various buses and control lines, such as a control line 722, a synchronization line 720, and one or more data buses 718. Control lines 722 and synchronization lines 720 provide control information and data and synchronization signals to transmit drive circuit 712, receive beamforming circuit 714 and continuous wave doppler circuit 716. The data bus 718 carries the RF ultrasound data from the digital front end board 710 to the digital processing board 726. Alternatively, the digital front end panel 710 may convert the RF ultrasound data into I, Q data pairs, which are then passed to the digital processing board 726.

Digital processing board 726 includes an RF and imaging module 728, a color flow processing module 730, an RF processing and doppler module 732, and a PCI link module 734. Digital processing board 726 performs RF filtering and processing, black and white image information processing, processing relating to color flow, doppler mode processing (e.g., relating to polling and continuous wave doppler). Digital processing board 726 also provides image filtering (e.g., speckle reduction) and scanner timing control. Digital processing board 726 may include other modules based on the ultrasound image processing functions provided by the system.

Module 728-. The RF and imaging module 728 performs various ultrasound related imaging, such as B-mode related image processing with RF data. The RF processing and doppler module 732 converts the incoming RF data into I, Q data pairs and performs doppler correlation processing on I, Q data pairs. Alternatively, the imaging module 728 may perform B-mode dependent image processing on the I, Q data pairs. The CFM processing module 730 performs image processing related to color flow on the ultrasonic RF data and/or I, Q data pairs. PCI link 734 manages the transfer of ultrasound data, control data, and other information between digital processing board 726 and main processing board 744 via PCI express bus 748.

The main processing board 744 includes a memory 750 (e.g., a serial ATA solid state device, a serial ATA hard drive, etc.), a VGA board 752 including one or more Graphics Processing Units (GPUs), one or more transceivers 760, one or more CPUs 752, and a memory 754. The main processing board (also referred to as a PC board) provides user interface management, scan conversion, and imaging loop management. The main processing board 744 may be connected to one or more external devices, such as a DVD player 756 and one or more displays 758. The main processing board includes communication interfaces, such as one or more USB ports 762 and one or more ports 764 configured to connect to peripheral devices. The main processing board 744 is configured to maintain communications with various types of network devices 766 and various network servers 768, such as wireless links (e.g., via USB connector 762 and/or peripheral connector 764) through transceivers 760 and/or network connections.

The network device 766 may represent a portable or desktop device, such as a smart phone, personal digital assistant, tablet device, portable computer, desktop computer, smart watch, ECG monitor, patient monitor, or the like. The main processing board 744 transmits the ultrasound images, ultrasound data, patient data, and other information and content to the network device for presentation to the user. The main processing board 744 receives inputs, requests, data inputs, etc. from the network device 766.

Network server 768 may represent a part of a medical network, such as a hospital, a medical care network, a third party medical care service provider, a medical device maintenance service, a medical device manufacturer, a government medical care service, or the like. The communication link to network server 768 may be the internet, a private intranet, a local area network, a wide area network, or the like.

The main processing board 744 is connected to the user interface control board 746 via a communication link 770. Communications link 770 transfers data and information between the user interface and main processing board 744. The user interface panel 746 includes one or more processors 772, one or more audio/video components 774 (e.g., speakers, display, etc.). User interface control panel 746 is coupled to one or more user interface input/output devices, such as an LCD touch panel 776, a trackball 778, a keyboard 780, and the like. Processor 772 manages the operation of LCD touch pad 776 and collects user inputs via touch pad 776, trackball 778 and keyboard 780, which are communicated to main processing board 744 in conjunction with embodiments herein.

Fig. 8 illustrates a block diagram of a portion of a digital front end plate 710 formed in accordance with embodiments herein. A set of duplexers 802 receive the ultrasonic signals of the respective channels through the PIB outputs 808. The ultrasonic signal is transmitted along standard processing circuitry 805 or continuous wave processing circuitry 812 based on the type of probe used. When processed by the standard processing circuit 805, the preamplifier and variable gain amplifier 804 processes the input ultrasonic reception signal, and then supplies it to the anti-aliasing filter 806 that performs anti-aliasing filtering.

According to one embodiment, retrospective transmit beam focusing may be applied directly to RF data acquired by the system or to transformed data according to different transforms, such as phase/quadrature (I/Q) transforms and the like.

In the embodiment of fig. 8, an example of transformation of RF data is disclosed. According to this example, the output of the filter 806 is supplied to an a/D converter 808 that digitizes the input analog ultrasonic reception signal. When a Continuous Wave (CW) probe is utilized, the signal therefrom is provided to a continuous wave phase converter, demodulator and summer 810 which converts the analog RF receive signal to I, Q data pairs. The CW I, Q data pairs are summed, filtered and digitized by a continuous wave processing circuit 812. The outputs from the standard or continuous wave processing circuits 805, 812 are then passed to a beamforming circuit 820 which filters, delays and sums the incoming digitized received signals with one or more FPGAs before passing the RF data to a digital processing board 826 (fig. 7). The FPGA receives focus data from memory 828. The focus data is used to manage the filtering, delay and summing operations performed by the FPGA in connection with beamforming. Beamformed RF or I/Q data is passed between beamforming circuits 820 and ultimately to digital processing board 726.

The digital front end panel 710 also includes a transmit module 822 that provides transmit drive signals to the respective transducers of the ultrasound probe. The beamforming circuit 820 includes a memory that stores transmit waveforms. The transmit module 822 receives the transmit waveform from the beamforming circuit 820 via line 824.

FIG. 9 shows a block diagram of digital processing board 726 according to embodiments herein. Digital processing board 726 includes

various processors

952 and 959 to perform various operations under the control of program instructions stored in respective memories, see 962 and 969. Main controller 950 manages the operation of digital processing board 726 and

processor

952 and 959. By way of example, one or more processors 952 may perform filtering, modulation, compression, and other operations, while another processor 953 performs colorflow processing. The main controller provides probe control signals, timing control signals, communication control, and the like. The main controller 950 provides real-time configuration information and synchronization signals associated with each channel to the digital front end board 710.

It should be clearly understood that the various arrangements and processes broadly described and illustrated with respect to the drawings, and/or one or more individual components or elements of such arrangements and/or one or more process operations associated with such processes, may be used independently or in conjunction with one or more other components, elements and/or process operations described and illustrated herein. Accordingly, while various arrangements and processes are broadly contemplated, described, and illustrated herein, it should be understood that they have been presented by way of illustration and not limitation, and may also be viewed as merely examples of possible operating environments in which one or more arrangements or processes may function or operate.

Aspects are described herein with reference to the accompanying drawings that show example methods, apparatus, and program products in accordance with various example embodiments. These program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus or information processing apparatus to produce a machine, such that the instructions, which execute via the processor of the apparatus, implement the functions/acts specified. The program instructions may also be stored in a device-readable medium that can direct a device to function in a particular manner, such that the instructions stored in the device-readable medium produce an article of manufacture including instructions which implement the specified function/act. The program instructions may also be loaded onto a device to cause a series of operational steps to be performed on the device to produce a device implemented process such that the instructions which execute on the device provide processes for implementing the functions/acts specified.

Optionally, aspects of the processes described herein may be performed on one or more networks on a network server. The network may support communications using any of a variety of commercially available protocols, such as transmission control protocol/internet protocol ("TCP/IP"), user datagram protocol ("UDP"), protocols operating in various layers of the open systems interconnection ("OSI") model, file transfer protocol ("FTP"), universal plug and play ("UpnP"), network file system ("NFS"), common network file system ("CIFS"), and AppleTalk. The network may be, for example, a local area network, a wide area network, a virtual private network, the internet, an intranet, an extranet, a public switched telephone network, an infrared network, a wireless network, a satellite network, and any combination thereof.

In embodiments utilizing a web page (web) server, the web server may run any of a variety of server or middle tier applications, including a hypertext transfer protocol ("HTTP") server, an FTP server, a common gateway interface ("CGI") server, a data server, a Java server, an Apache server, and a business applicationAnd (4) a server. The server can also be capable of executing programs or scripts in response to requests from the user device, such as by executing one or more web applications, which can be implemented in any programming language (e.g., a web browser application)

C. C #, or C + +, or any scripting language (e.g., Ruby, PHP, Perl, Python, or TCL), as well as combinations thereof. The server may also include a database server, including but not limited to, a database server

And

commercially available database servers and servers such as MySQL, Postgres, SQLite, MongoDB, and any other server capable of storing, retrieving, and accessing structured or unstructured data. The database servers may include workbench servers, document-based servers, unstructured servers, relational servers, non-relational servers, or combinations thereof, and/or other database servers.

Embodiments described herein may include the various data stores and other memory and storage media described above. These may reside in various locations, such as on a storage medium local to (and/or resident in) one or more computers or remote from any or all computers in the network. In one particular set of embodiments, the information may reside in a storage area network ("SAN") familiar to those skilled in the art. Similarly, any necessary files for performing the functions attributed to a computer, server, or other network device may be stored locally and/or remotely as appropriate. Where the system includes computerized devices, each such device may include hardware elements that are electrically connected via a bus, including, for example, at least one central processing unit ("CPU" or "processor"), at least one input device (e.g., a mouse, keyboard, controller, touch screen, or keypad), and at least one output device (e.g., a display device, printer, or speaker). Such a system may also include one or more storage devices, such as magnetic disk drives, optical storage devices, and solid-state storage devices (e.g., random access memory ("RAM") or read-only memory ("ROM")), as well as removable media devices, memory cards, flash memory cards, and the like.

Such devices may also include a computer-readable storage medium reader, a communication device (e.g., a modem, a (wireless or wired) network card, an infrared communication device, etc.), and the above-described working memory. The computer-readable storage media reader can be connected to or configured to receive computer-readable storage media representing remote, local, fixed, and/or removable storage devices, as well as storage media for temporarily and/or more permanently containing, storing, transmitting, and retrieving computer-readable information. The system and various devices also typically include a number of software applications, modules, services or other elements, including an operating system and applications (e.g., client applications or a web browser), located within at least one working memory device. It should be understood that alternative embodiments may have many of the same variations as the above-described embodiments. For example, customized hardware might also be used and/or particular elements might be implemented in hardware, software (including portable software, such as applets), or both. In addition, connections to other computing devices (e.g., network input/output devices) may be employed.

Various embodiments may also include receiving, sending, or storing instructions and/or data implemented in accordance with the foregoing description on a computer-readable medium. Storage media and computer-readable media containing code or portions of code may include any suitable media known or used in the art (e.g., including, but not limited to, storage media and communication media), volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage and/or transmission of information such as computer-readable instructions, data structures, program modules or other data, including RAM, ROM, electrically erasable programmable read-only memory ("EEPROM"), flash memory or other memory technology, compact disc read-only memory ("CD-ROM"), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a system device. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the various embodiments.

The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the claims that follow.

Other variations are within the spirit of the present disclosure. Accordingly, while the disclosed technology is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the appended claims.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the disclosed embodiments (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. The term "connected," when unmodified and referring to physical connection, is to be construed as being partially or fully contained, attached, or connected together, even if there is some intervention. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Unless otherwise stated or contradicted by context, use of the term "group" (e.g., "a group of objects") or "subset" should be interpreted to include a non-empty set of one or more members. Further, unless otherwise indicated or contradicted by context, the term "subset" of a corresponding set does not necessarily denote an appropriate subset of the corresponding set, but the subset and the corresponding set may be equal.

The operations of processes described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The processes described herein (or variations and/or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more application programs) that are executed collectively on one or more processors by hardware or a combination thereof. The code may be stored on a computer-readable storage medium, for example, in the form of a computer program comprising a plurality of instructions executable by one or more processors. The computer readable storage medium may be non-transitory.

Preferred embodiments of this disclosure are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the embodiments of the disclosure to be practiced otherwise than as specifically described herein. Accordingly, the scope of the present disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

Claims

1. A method for automatically setting parameters of a doppler mode in real time, comprising:

-transmitting an ultrasound beam in a target volume and receiving a reflected beam from the target volume;

-extracting a doppler signal from said reflected beam;

-processing the doppler signals to identify a region in which the doppler signals indicate the presence of blood flow, and processing the doppler signals relating to the region to automatically determine one or more of the following parameter settings:

locate a color doppler ROI and/or doppler sample gate, determine and apply the optimal color doppler beam steering angle, set the doppler correction angle,

wherein the processing the Doppler signals comprises:

analyzing the shape of the identified doppler region by processing the corresponding doppler signal to determine:

a) the location of the blood flow with the most significant intensity;

b) the direction of blood flow at the location determined in a);

determining an optimal position of a color doppler ROI and/or a doppler sampling gate from the position of the blood flow and positioning the color doppler ROI and/or the sampling gate at the position;

the steering angle and/or doppler correction angle of the transmit beam is determined from the direction of blood flow,

wherein analyzing the shape of the identified Doppler region for determining the location of blood flow having the most significant intensity comprises:

-creating a virtual doppler image of blood flow from the doppler signals;

-calculating a maximum value of a pixel or voxel of the virtual doppler image and selecting the location of the maximum value of said pixel or voxel as the location of the blood flow, an

Wherein analyzing the shape of the identified Doppler region for determining the direction of blood flow comprises:

-applying four directional filters to the virtual doppler image at locations having pixel maxima, the directional filters being respectively oriented along one of four directions, each direction being rotated by 45 ° with respect to the adjacent direction;

-combining the outputs of the four directional filters to obtain a vector;

-determining the direction of blood flow from the direction of said vector.

2. The method of claim 1, wherein analyzing the shape of the identified doppler region is based on morphological features of blood flow determined from doppler signals.

3. The method of claim 1 or 2, wherein determining the direction of blood flow comprises:

-applying four directional filters to the virtual doppler image at locations having pixel maxima, the directional filters being oriented along the following directions, respectively: according to the symbols 0 ° -180 °, 45 ° -215 °, 90 ° -270 ° and 135 ° -315 °, said directions being defined by directions defined by axes passing through the direction of an goniometer centred on the central position of the blood flow, the goniometer being aligned with the axes of a cartesian system defining two dimensions of an image having 0 ° -180 ° axes and 90 ° -270 ° axes;

-combining the outputs of the four directional filters to form a vector having orthogonal components x and y having the following values: x ═ the output of the filter with direction 0 ° -180 ° - (the output of the filter with direction 90 ° -270 °), and Y ═ the output of the filter with direction 45 ° -215 ° - (the output of the filter with direction 135 ° -315 °;

-determining the phase of the vector and calculating the angle of the blood flow direction from said phase.

4. The method of claim 1, wherein the virtual doppler image is sub-sampled.

5. The method of claim 1, wherein the virtual doppler image is filtered by a smoothing filter.

6. The method of claim 3, wherein the blood flow direction angle is calculated by the function:

7. a method according to claim 3, wherein the normalized modulus Q of the vector is calculated and used as a quality factor for the direction estimation.

8. The method of claim 7, wherein the normalized modulus Q is calculated by the function:

wherein:

f0 is the output of the filter with a direction of 0-180;

f45 is the output of the filter with a direction of 45-215;

f90 is the output of the filter with a direction of 90-270;

f135 is the output of the filter with a direction of 135-315.

9. The method of claim 7, further comprising:

-defining a threshold value for the value of the normalized modulus;

-calculating said normalized modulus Q;

10. An ultrasound imaging system for automatically setting doppler mode in real time, comprising:

-an ultrasound probe comprising an array of transducers, said probe emitting ultrasound beams in a target region where blood flow is present and receiving echo signals reflected by said target region;

-a beam former;

-a doppler processor for generating a doppler signal from the echo signal;

-an image processor for generating a virtual doppler image of the blood flow from the doppler signals in the target region;

wherein,

the color doppler ROI and/or doppler sample gate positioning processor and steering angle and/or doppler correction angle processor are configured to:

processing the Doppler signal;

determining data relating to morphological features of blood flow; and

calculating an optimal position of a color Doppler ROI and/or a Doppler sampling gate and a steering angle and/or a Doppler correction angle from the morphological feature data, an

Wherein the color Doppler ROI and/or Doppler sample gate positioning processor and steering angle and/or Doppler correction angle processor are configured to analyze the shape of the identified Doppler region for determining the direction of blood flow, comprising:

-combining the outputs of the four directional filters to obtain a vector;

-determining the direction of blood flow from the direction of said vector.

11. The ultrasound imaging system of claim 10, wherein the positioning processor is arranged in combination with a color doppler image processing unit configured to determine the maximum pixel value and its location to generate an image from the doppler signals, wherein the color doppler image processing unit comprises a ROI and/or sampling gate management unit for automatically positioning the ROI and/or sampling gate at the location having the pixel maximum value.

12. The ultrasonic imaging system according to claim 10, wherein the steering angle and/or Doppler correction angle processor is provided in combination with the color Doppler image processing unit to generate an image from the Doppler signal, and the steering angle and/or Doppler correction angle processor includes a filter unit provided with four directional filters, each directional filter being oriented in one of four directions, respectively, each direction being rotated by 45 ° with respect to an adjacent direction,

the outputs of the four directional filters are input to a steering angle and/or doppler correction angle processor to calculate the blood flow direction and a quality factor for the calculated direction.

13. The ultrasound imaging system of claim 12, wherein the steering angle and/or doppler correction angle processor is configured to calculate a blood flow direction angle as a function of:

where X ═ is (the output of the filter with direction 0 ° -180 ° -the output of the filter with direction 90 ° -270 °, and Y ═ is (the output of the filter with direction 45 ° -215 ° -the output of the filter with direction 135 ° -315 °.

14. The ultrasound imaging system of claim 12, wherein the steering angle and/or doppler correction angle processor is configured to calculate a normalized modulus Q of the vector for use as a quality factor for the direction estimate as follows:

wherein:

f0 is the output of the filter with a direction of 0-180;

f45 is the output of the filter with a direction of 45-215;

f90 is the output of the filter with a direction of 90-270;

f135 is the output of the filter with a direction of 135-315.

15. The ultrasound imaging system of claim 11 or 12, further comprising a sampling unit for subsampling the virtual doppler image and a filter for smoothing the subsampled image.

16. The ultrasound imaging system of claim 14, wherein the steering angle and/or doppler correction angle processor includes a memory for storing a threshold value for the quality factor, and a comparator for comparing the calculated quality factor to the threshold value, an output of the comparator being read by the steering angle and/or doppler correction angle processor for determining whether the calculated flow direction can be used to determine the steering angle and/or doppler correction angle of the transmit beam.

17. Readable medium on which instructions are encoded for configuring a general-purpose processor and peripheral devices connected to the general-purpose processor, such that the processor and one or more of said peripheral devices perform the functions of an operating unit required for the method according to claim 1, said medium being read by a reader unit or stably installed as a peripheral device of the processor.